Honestly? Dunno. My sister's dogs spent daytimes while Sis was at work with Grandma. Sometimes at Grandma's house, sometimes at their own house. We always said both dogs weren't sure if they belonged to Sis or to Grandma but it worked out ok. But this was on a daily basis, not weekends and then a gap of five days between the next visit. And nights were always at Sis's house.
I do wonder if it might be too disturbing for a puppy to, in a sense, change homes so many times at a young age.